The present invention relates to a golf club head molded from synthetic resin as a main material and a mold for the same, and more particularly to a golf club head whose shaft fit hole is able to be molded with high accuracy by using a simple mold structure and a mold for molding the same.
In prior art wood type golf club heads formed from synthetic resin as a main material, as shown in FIG. 23, a shaft fit hole 107 is provided in the heel side end portion of the club head main body 101 such that the shaft fit hole 107 extends from the upper end of the hosel portion 102 to the bottom of the sole portion 103. Generally, in molding a golf club head of this type, a mold is used which is divided into two halves; upper and lower molds, and a shaft molding pin for molding the above-mentioned shaft fit hole 107 is mounted in this mold.
However, because such a shaft molding pin is mounted therein, the mold used has to be made larger and the structure of the mold is also more complicated. In addition, the complicated structure of the mold makes it extremely difficult to set the shaft molding pin at a precise predetermined position in the mold. Due to this, deviations in the position and/or the angle of inclination of the shaft molding pin occur during the molding operation, which leads to poor quality in the golf club heads molded.
Moreover, players require various types of golf clubs having different loft angles (angles at which the club face inclines with reference to the axis of the club shaft) and lie angles (angles at which the club shaft inclines with reference to the ground when the gap between the sole portion of the club head main body and the ground at the toe end is substantially the same as the gap at the heel end). However, it is not possible to mold such various types of golf club heads using one type of a mold, and due to this, typically each club's specification require a different type of a mold. Thus many types of molds have to be prepared. This inevitably increases the manufacturing costs of golf club heads.
An object of the present invention therefore is to provide a golf club head molded from a synthetic resin as a main material whose shaft fit hole is molded through a simple mold structure without using the above-mentioned troublesome shaft molding pin.
Another object of the present invention is to provide a golf club head whose shaft fit hole is able to be molded with high accuracy.
A further object of the present invention is to make it possible to manufacture various types of golf club heads having different lie and loft angles using one type of a mold with high manufacturing efficiency.
A still further object of the present invention is to provide a mold enabling the molding of the above-mentioned golf club head in an easy fashion.